#pragma comment(linker, "/STACK:10000000")
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <set>
#include <map>
#include <cstdio>
#include <cassert>
#include <string>
#include <cstring>
#define ldb long double
#define LL long long
#define fi first
#define se second
#define fill(a, c) memset(a, c, sizeof(a))
#define sqr(a) ((a) * (a))
#define nextLine() {int c = 0; while((c = getchar()) != 10 && c != EOF);}
#define getBit(mask, k) (((mask) / pw[k]) % pw[1])
#define setBit(mask, k, l) (((mask) / pw[k + 1] * pw[1] + (l)) * pw[k] + ((mask) % pw[k]))
#define debug(a) cerr << #a << " = " << a << " ";
#define debugl(a) cerr << #a << " = " << a << "\n";
const ldb LDINF = 9128739847123.00;
const ldb eps = 1e-9;
const int INF = 1 << 30;
const ldb pi = fabsl(atan2(0.0, -1.0));
using namespace std;

int n, k, m;
int a[100000];

void Load()
{
	cin >> n >> m >> k;
	int i;
	for (i = 0; i < n; i++)
	{
		scanf("%d", &a[i]);
	}
}

void Solve()
{
	int res = 0;
	if (n % 2 == 0)
	{
		cout << 0; return;
	}
		int mx = 1000000;
		for (int j = 0; j < n; j++)
		{
			if (j % 2 == 0)
				mx = min(mx, a[j]);
		}
		mx = min((LL)mx, (LL)k * (LL)m / ((LL)n / 2 + 1));
		for (int j = 0; j < n && j < 2 * m; j++)
		{
		 	if (j % 2 == 0)
		 		a[j] -= mx;
		 	else a[j] += mx;
		}
		res = mx;
	cout << res;

}

#define file "a"
int main()
{
	#ifndef ONLINE_JUDGE
		freopen(file".in", "rt", stdin);
		freopen(file".out", "wt", stdout);
	#endif
	Load();
	Solve();
	return 0;
}
